The stroke of a brake pedal in a vehicle is normally computed on the basis of the detection result of a stroke sensor or master cylinder pressure sensor. A braking force control device provided in the vehicle controls the wheel cylinder pressure so that braking force is applied to the vehicle in accordance with the computed stroke, thereby applying appropriate braking force to the vehicle. With regard to abnormality determination in this brake control device, for example, there has been proposed an abnormality determining device in which an open/close valve is opened when the detection value of a stroke sensor is less than a reference value of a master cylinder pressure sensor, and the detection value of the master cylinder pressure sensor and the detection value of a wheel cylinder pressure sensor are compared against each other, and it is determined whether the master cylinder sensor is abnormal or the stroke of the brake pedal sensor is abnormal (see, for example, Japanese Patent Application Publication No. 11-301463 (JP-A-11-301463)).
A braking force control with an electromagnetic valve or the like in a vehicle is carried out by using the stroke of a brake pedal detected by a stroke sensor. Thus, for example, if it is determined that the stroke sensor is abnormal, it is necessary to take a countermeasure such as canceling the braking force control and transmitting the master cylinder pressure to a wheel cylinder as it is. However, such switching of braking force control may impair the brake feeling for the driver since it affects the depression force on the brake pedal.